Historically, schizophrenia (SZ) and bipolar (BP) disorder have been considered as non-overlapping nosological entities, with distinctive clinical characteristics, unique treatment regimens and separate (albeit unknown) etiologies.
The schizophrenic disorders are a group of syndromes manifested by massive disruption of thinking, mood, and overall behavior as well as poor filtering of stimuli. Diagnosis of schizophrenic disorder is currently based upon the presence of a number of behavioral characteristics of at least six months duration including: slowly progressive social withdrawal usually often accompanied by a deterioration in personal care; loss of ego boundaries with the inability to perceive oneself as a separate entity; loose thought associations, often with slowed thinking or overinclusive and rapid shifting from topic to topic; autistic absorption in inner thoughts and frequent sexual or religious preoccupations; auditory hallucinations, often of a derogatory nature; and delusions, frequently of grandiose or persecutory nature. Frequent additional signs include: flat effect and rapidly alternating mood shift irrespective of circumstances; hypersensitivity to environmental stimuli, with a feeling of enhanced sensory awareness; variability or changeable behavior incongruent with the external environment; concrete thinking with the inability to abstract; inappropriate symbolism; impaired concentration worsened by hallucinations and delusions; and depersonalization, wherein one behaves like a detached observer of one's own actions. Diagnosis of a schizophrenic disorder based upon these behaviors can thus be quite arbitrary and is influenced by sociocultural factors and schools of psychiatric thought. At present, there is no laboratory method (e.g., molecular diagnostic) for diagnosis or confirmation of a diagnosis of schizophrenia.
Bipolar disorder, also known as manic-depressive illness, involves cycles of mania and depression. Signs and symptoms of mania include: extreme irritability and distractibility; excessive euphoric feelings; a sustained period of behavior that is different from the usual behavior; increased energy activity, restlessness, racing thoughts and rapid talking; decreased need for sleep; unrealistic beliefs in one's abilities and powers; uncharacteristically poor judgment; increased sexual drive; abuse of drugs, particularly cocaine, alcohol and sleeping medications; obnoxious, provocative or intrusive behavior and denial that anything is wrong. Signs and symptoms of depression include: persistent sad, anxious or empty mood; feeling of hopelessness or pessimism; feeling of guilt, worthlessness or helplessness; loss of interest or pleasure in ordinary activities; decreased energy, a feeling of fatigue or of being “slowed down”; difficulty concentrating, remembering and making decisions; restlessness and irritability; sleep disturbances; loss of appetite and weight, or weight gain; chronic pain or other persistent bodily symptoms that are not caused by physical disease; and thoughts of death or suicide. Most people with manic-depressive illness can be helped with treatment. However, manic-depressive illness, which is currently diagnosed by symptoms alone, is often not recognized by the patient, relatives, friends and even physicians. If left untreated, bipolar disorder tends to worsen, and the person experiences episodes of full-fledged mania and clinical depression.
Accordingly, a great need exists for better, more definitive diagnostic markers and methods for diagnosing neuropsychiatric disorders including schizophrenia and bipolar disorder and other related disorders.